1. Field of the Invention
An adjustable-force energy absorbing device is disclosed including first and second support members connected for sliding movement in a direction parallel with the steering shaft axis of an automotive vehicle, the first support member being fixed and secured to the vehicle chassis, and the second support member being movable and connected with the outer support tube of the steering mechanism. Upon impact, the second support member is displaced from its normal first position spaced from one end of the first support member toward a second position adjacent the first support member one end. This displacement is resisted by at least one U-shaped energy absorbing element, the number and/or degree of operability of the energy absorbing elements being controlled by at least one impact-responsive pyrotechnic device.
2. Description of the Related Art
As evidenced by the prior U.S. Pat. No. 4,989,898, to Yamaguchi, et al., the British patent No. 1,584,984 and the German patent No. DE 195 42 491 C1, among others, it is well known in the patented prior art to provide energy storing means for absorbing the impact energy developed in a steering mechanism upon impact of an automotive vehicle. As shown by these patents, U-shaped energy absorbing means are often connected between the steering means of the vehicle and its chassis.
The increasing improvement of safety with regard to steering columns requires designers to master all of the parameters of energy absorption systems. Regarding the process involved in the absorption of energy on a steering column, it is thus envisaged that one would modulate that energy absorption according to the characteristics of the driver, such as especially the weight of the driver, whether or not the driver's seat belt has been fastened, the driver's position with respect to the steering wheel as well as the speed of the vehicle that acts upon the wheel in case of an impact.
The present invention was developed to provide an adjustable-free energy absorption device that works directly according to the direction of the shock and that puts into action simple energy absorption elements that are easy to manufacture. The present invention makes it possible in a quantified manner to absorb all or a portion of the required energy to be dissipated, which will take into account the characteristics of the driver and the vehicle while being easily installed in the space occupied by existing steering columns.